How to run a third party library method that potentially throws a StackoverflowException in a safe way c#

Question

I'm using a third party library that converts excel files to PNG for preview purposes. Sometimes the excel it's too complex, and the library fails with a StackoverflowException. That's ok, because I don't except all files to be converted, but I can't catch the exception and give the user other option to download the file (Stackoverflow exceptions aren't catcheables)

I try to run in other thread using Task.Run() and even with a new request, but the original request stalls and I'm not able to control the fail.

Attempt 1 using Task.Run()

    public string ExcelAsPNGUrl() {
        try {
            var TempFolder = @"/Content/Temp/";
            var UniquePreviewFileName = ArchivoURL.Replace("/", "_") + ".png";
            if (!System.IO.File.Exists( HttpContext.Current.Server.MapPath(TempFolder + UniquePreviewFileName))) {
                var asyncTask = Task.Run(() => {
                    var UniquePreviewFileName = ArchivoURL.Replace("/", "_") + ".png";
                    var workbook = new Spire.Xls.Workbook();
                    workbook.LoadFromFile(HttpContext.Current.Server.MapPath(ArchivoURL));
                    var sheet = workbook.Worksheets[0];
                    sheet.SaveToImage(HttpContext.Current.Server.MapPath(TempFolder + UniquePreviewFileName));
                    return TempFolder + UniquePreviewFileName;
                });
                return asyncTask.Result;
            }
            return TempFolder + UniquePreviewFileName;
        }
        catch (Exception) {
            return "";
        }
    }

Attempt 2 using WebClient

    public string ExcelAsPNGUrl() {
        try {
            var TempFolder = @"/Content/Temp/";
            var UniquePreviewFileName = ArchivoURL.Replace("/", "_") + ".png";
            if (!System.IO.File.Exists( HttpContext.Current.Server.MapPath(TempFolder + UniquePreviewFileName))) {
                var client = new System.Net.WebClient();
                var retval = client.DownloadString(Sitio.URI + $"/system/GenerateExcelPreview?ArchivoURL={ArchivoURL}");
            }
            return TempFolder + UniquePreviewFileName;
        }
        catch (Exception) {
            return "";
        }
    }

How can I call the library safely from my web app?

Have you seen [this related post](https://stackoverflow.com/a/54584830/1911064)? It might help to increase the stack size. — Axel Kemper, Jul 04 '22 at 21:09
@AxelKemper I really don't want to do that, because I can't be sure the new size will be enough. Starting to think about writing an standalone exe and calling it with Process.Start — Eduardo Molteni, Jul 04 '22 at 21:11
I might delete the question, I've found https://stackoverflow.com/questions/206820/how-do-i-prevent-and-or-handle-a-stackoverflowexception that covers all cases — Eduardo Molteni, Jul 04 '22 at 21:14
Finally solved the problem making another Ajax request and catching the fail there — Eduardo Molteni, Jul 05 '22 at 12:05

How to run a third party library method that potentially throws a StackoverflowException in a safe way c#

Attempt 1 using Task.Run()

Attempt 2 using WebClient

0 Answers0